rear defogger / average mpg

Feb 29, 2012 1 Replies

Bought a used 2004 Camry 2.4 XLE with 80K miles last week. It rides nice and is quiet. There are two minor things about it that bother me.


  1. The digital readout for the average mpg has steadily risen from

28.0 to 28.9 since I've owned it. After filling up today and doing the calculation of miles driven divided by gallons pumped I came up with
24.7 mpg. Why such a disparity?


  1. The rear defogger seems quite anemic to me. We haven't had much frost but it can't seem to clear even dew from the back window in the ten minutes or so to work. I mean there's no separation occurring between the filaments at all. The thing is on and you can see it barely working, but its weak and slow.


Two different ways of measuring things give two different answers, UNLESS you are very careful to cross calibrate them and UNLESS the two methods are just not so very accurate. Both UNLESS's are probably in play here.

The schematic doesnt show anything really esoteric about this system. If you are getting SOME indication of warming, you may simply have a poor ground connection from the heating grid. Most of the other things, relay, switch, etc, are usually (but not always) either good or not good.

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